1. Field of the Invention
The present invention relates to a method for manufacturing an isolation structure and a memory, and in particular, to a method for manufacturing a trench isolation structure and a non-volatile memory.
2. Description of Related Art
A memory is a semiconductor device designed to store data. As the microprocessors in computers become more powerful than ever to be compatible with growingly massive amount of programs and calculations executed by the software, the capacity of the memory needs to be increased accordingly. The developments of memories move toward manufacturing large-storage and low-cost memories to meet the requirements in the semiconductor manufacture.
Among various kinds of memory products, the non-volatile memory is a kind of memory characterized by the advantages that it allows multiple data storing, reading or erasing operations and the stored data therein will be retained after the device is not powered. Hence, the non-volatile memory has become a widely adopted memory device in personal computers and electronic equipments.
In regard to the operation of the non-volatile memory, generally, if the coupling ratio of a device is large, the work voltage required for operating the device is low. The method of increasing the coupling ratio includes increasing an overlap area between the floating gate and the control gate, reducing the thickness of the dielectric layer between the floating gate and the control gate, and increasing the dielectric constant of the dielectric layer between the floating gate and the control gate. However, the general non-volatile memory usually has a problem of an overly low coupling ratio. The problem affects the electron flowing efficiency when a programming operation or an erasing operation is performed. Therefore, the work efficiency of the non-volatile memory is reduced.